Cross-field control of transducers



May 24, 1966 BAYCURA 3,253,242

CROSS-FIELD CONTROL OF TRANSDUCERS Filed June 29, 1961 lNVENTOR m ORESTES M. BAYCURA ATTORNEY United States Patent 3,253,242 CROSS-FIELD CONTROL OF TRANSDUCERS Orestes M. Baycura, Vestal, N.Y., assignor to International Business Machines Corporation, New York, N.Y., a corporation of New York Filed June 29, 1961, Ser.No. 120,743 4 Claims. (Cl. 336-73) This invention relates generally to transducers and it has reference in particular to the control of transducers by cross-field magnetic flux.

It is one of the objects of this invention to provide for passing a current through a core of magnetic material having transducer windings thereon for producing a crossfield control flux in the core that is orthogonal to the principal transducer flux.

Another object of this invention is to provide in a transducer having a laminated core of magnetic material for making electrical connections to the laminations at spaced points so as to provide for conducting a cross-field producing current through one or more portions of the laminations.

Yet another object of this invention is to provide for making a press fit bet-ween a nonmagnetic conductor and each of a plurality of laminations of magnetic material in the core of a transducer for passing a cross-field producing current through selected portions of said cores.

Still another object of the invention is to provide for electrically bonding a conductor to each of a plurality of laminations of a transducer at spaced points so that a cross-field control current can be m-ad-e'to flow through the laminations between said points for controlling the transducer.

It is also an object of this invention to provide for utilizing a magnetic tape material wound about a central conductor as a core for a transducer so that the central conductor may be utilized to produce a cross-field flux in the core for controlling the inductive coupling between windings positioned on the core.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention as illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a schema-tic showing of a transducer embodying the invention in one of its forms.

FIG. 2 is a schematic showing of a different embodiment of the invention.

FIG. 3 illustrates yet another form of the invention.

FIG. 4 is an enlarged partial view of a different method of construction which may be utilized in connection with the showings of FIGS. 2 and 3.

FIG. 5 is an enlarged partial view of a different method of connecting the laminations which may be utilized in connection with the showings of FIGS. 2 and 3.

Referring particularly to FIG. 1, the reference numeral denotes generally a transducer in which input and output windings 12 and 14 are positioned on a magnetic core which comprises one or more layers of turns of magnetic tape material 15 wound in .a helical toroid about one or more turns of a conductor 17 arranged generally in a circular loop.

The windings 12 and 14 are inductively coupled by the core of magnetic tape material 15. By connecting thewinding 12, for example, to an alternating current source an output may be obtained from the winding 14 under normal operating conditions and vice versa. By circulating a control current through the conductor 17 a magnetic flux is introduced in the tape material 15 which is substantially orthogonal to the flux produced by the winding 12 and therefore operates to control the magnetic coupling be- 3,253,242 Patented May 24, 1966 rent can be made to have a relatively large amount of control of the coupling between windings 12 and 14.

In one embodiment :of the invention as shown in FIG. 1, a /2 inch wide tape of molybdenum permalloy square loop magnetic tape material approximately 2 mils thick was wrapped about several turns of insulated copper wire arranged in a circular loop so as to provide approximately 10 layers of the magnetic tape about the 4 inch diameter coil. A current of less than 1 ampere in the winding 17 was sufficient to control the coupling between the windings 12 and 14 over a relatively wide operating range on the order of 2: 1.

Referring to FIG. 2, the reference numeral 20 designates a transformer having a rectangular core 22 with input and output windings 23 and 24 respectively arranged thereon. Electrical connections are made to the material of the core 22 such as by means of conductors 26 and 27 for the purpose of passing a saturation control current through a portion of the core 22 to produce an orthogonal or cross-field magnetic flux for controlling the inductive coupling between the windings 23 and 24. The connections 26 and 27 may be located as shown, or similar connections may be made at other spaced-apart points on the core 22 as illustrated by the similar conductors '28 and 29.

The connections of the conductors 2-6 and 27 may, for example, be made as shown in FIG. 4 by driving nonmagnetic pins 30 of copper or the like through holes 32 in laminations to provide a snug or press fit and connecting the conductors thereto. Other means of making electrical connections to the laminations of the core 22 may be utilized, for example by welding or soldering conductors 34 to the edges of the laminations by means of welds 35 or the like.

As is shown in FIG. 3 the connections may be made at any of a number of different points so as to pass current through different select portions of the core, being for example made to opposite ends of the core 22 and a variable control current pass through the two halves of the core by connecting a battery 3.6 in circuit with the conductors 26 and 27 and utilizing means such as a variable resistor 38 for controlling the amount of current circulating in the core. One embodiment of the invention utilizes a core 22 of transformer silicon iron having a size of approximately 2 inches by 4 inches with a inch cross-section. A current of 5 to 6 amperes passed through the laminations of the core controls the coupling between the windings 23 and 24 so as to produce as much as a 15% change in the output which is more than adequate for regulating purposes.

Referring to the above description and the accompanying drawings, it will be apparent that we have provided in a simple and effective manner for controlling the coupling between transducer windings by passing a cross-field producing current through the transducer core. The utilization of a tape wound core in a transducer device particularly lends itself to a wide range of coupling control between the input and output windings for a relatively small control current.

While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In a power transformer, a closed core comprising a toroidal helix of magnetic tape material, input and output windings disposed about said core in inductively cou- 60 cycle power source, and a conductor threaded through the toroid for producing a cross-field control flux in said core to control the coupling between said input and output windings.

2. A transducer comprising a non-saturating toroidal core consisting of a helix of magnetic tape material, primary and secondary windings disposed about portions of said core in inductively coupled relation, means connecting the primary winding to an alternating current power source, and means controlling the inductive coupling between said windings including a direct current control winding extending through at least a portion of the helix.

3. In an alternating current transformer,

(a) a toroidal control winding comprising a plurality of turns of an insulated conductor,

(b) a non-saturating core comprising a plurality of layers of'a relatively thin tape of magnetic material and (c) primary and secondary windings disposed about the core and control winding in inductively coupled relation.

4. An alternating current transformer comprising,

(a) a cross-field flux control winding consisting of a plurality of closely spaced turns of an insulated conductor,

(b) a non-saturating core comprising a plurality of turns of a molybdenum permalloy square loop magwound helically about said toroidal control winding,

netic tape mate-rial wound in a helix about the turns of the control winding,

(c) primary and secondary windings wound about the core and control winding in inductively coupled relation, and means connecting the primary winding to an alternating current source.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Buck and Frank: Nondestructive Sensing of Magnetic Cores, Communications and Electronics for J anuary 1 954 (#31), pp. 822830.

Langsdorf, abstract of abandoned application Serial No. 212,266, published June 30, 1953 at 671 0G. 1499.

ROBERT K. SOHAEFER, Primary Examiner.

JOHN F. BURNS, Examiner. 

1. IN A POWER TRANSFORMER, A CLOSED CORE COMPRISING A TOROIDAL HELIX OF MAGNETIC TAPE MATERIAL, INPUT AND OUTPUT WINDINGS DISPOSED ABOUT SAID CORE IN INDUCTIVELY COUPLED RELATION, MEANS CONNECTING THE INPUT WINDING TO A 60 CYCLE POWER SOURCE, AND A CONDUCTOR THREADED THROUGH THE TOROID FOR PRODUCING A CROSS-FIELD CONTROL FLUX IN SAID CORE TO CONTROL THE COUPLING BETWEEN SAID INPUT AND OUTPUT WINDINGS. 